How relevant is alkylation of nucleic acids in chemical carcinogenesis? Is it a causal event? This venerable question is still in want of an answer. This project attempts to derive a statistical correlation of the carcinogenicity of known alkylating carcinogens with product patterns (O- vs. N-alkylation) in their reactions with nucleic acid constituents. These O:N ratios of alkylated products will constitute a chemical characteristic of the carcinogens. Such correlation will provide the molecular basis to examine the causal involvement of alkylation of nucleic acids in carcinogenesis.